Re: [Qemu-devel] [PATCH V2 3/6] libqblock error handling

[Blue Swirl]

On Wed, Sep 12, 2012 at 2:58 AM, Wenchao Xia <address@hidden> wrote:
> 于 2012-9-12 4:32, Blue Swirl 写道:
>
>> On Mon, Sep 10, 2012 at 8:26 AM, Wenchao Xia <address@hidden>
>> wrote:
>>>
>>>    This patch contains error handling APIs, which user could call them to
>>> get error details.
>>>
>>> Signed-off-by: Wenchao Xia <address@hidden>
>>> ---
>>>   libqblock/libqblock-error.c |   60
>>> +++++++++++++++++++++++++++++++++++++++++++
>>>   libqblock/libqblock-error.h |   50 +++++++++++++++++++++++++++++++++++
>>>   2 files changed, 110 insertions(+), 0 deletions(-)
>>>   create mode 100644 libqblock/libqblock-error.c
>>>   create mode 100644 libqblock/libqblock-error.h
>>>
>>> diff --git a/libqblock/libqblock-error.c b/libqblock/libqblock-error.c
>>> new file mode 100644
>>> index 0000000..d5ebabf
>>> --- /dev/null
>>> +++ b/libqblock/libqblock-error.c
>>> @@ -0,0 +1,60 @@
>>> +/*
>>> + * QEMU block layer library
>>> + *
>>> + * Copyright IBM, Corp. 2012
>>> + *
>>> + * Authors:
>>> + *  Wenchao Xia   <address@hidden>
>>> + *
>>> + * This work is licensed under the terms of the GNU LGPL, version 2 or
>>> later.
>>> + * See the COPYING.LIB file in the top-level directory.
>>> + *
>>> + */
>>> +
>>> +#include "libqblock-error.h"
>>> +#include "libqblock-internal.h"
>>> +
>>> +void qb_error_get_human_str(struct QBroker *broker,
>>> +                            char *buf, int buf_size)
>>
>>
>> size_t buf_size
>>
>   OK.
>
>
>>> +{
>>> +    const char *err_ret_str;
>>> +    switch (broker->err_ret) {
>>> +    case QB_ERR_MEM_ERR:
>>> +        err_ret_str = "Not enough memory.";
>>> +        break;
>>> +    case QB_ERR_INTERNAL_ERR:
>>> +        err_ret_str = "Internal error.";
>>> +        break;
>>> +    case QB_ERR_INVALID_PARAM:
>>> +        err_ret_str = "Invalid param.";
>>> +        break;
>>> +    case QB_ERR_BLOCK_OUT_OF_RANGE:
>>> +        err_ret_str = "request is out of image's range.";
>>> +        break;
>>> +    default:
>>> +        err_ret_str = "Unknow error.";
>>> +        break;
>>> +    }
>>> +    if (broker == NULL) {
>>> +        snprintf(buf, buf_size, "%s", err_ret_str);
>>> +        return;
>>> +    }
>>> +
>>> +    if (broker->err_ret == QB_ERR_INTERNAL_ERR) {
>>> +        snprintf(buf, buf_size, "%s %s errno [%d]. strerror [%s].",
>>> +                     err_ret_str, broker->err_msg,
>>> +                     broker->err_no, strerror(-broker->err_no));
>>> +    } else {
>>> +        snprintf(buf, buf_size, "%s %s",
>>> +                     err_ret_str, broker->err_msg);
>>> +    }
>>
>>
>> Please NUL terminate the string.
>>
>   snprintf will add "\0" automatically, could u explain more about this?

Sorry, I claim temporary insanity.

>
>
>>> +    return;
>>> +}
>>> +
>>> +int qb_error_get_errno(struct QBroker *broker)
>>> +{
>>> +    if (broker->err_ret == QB_ERR_INTERNAL_ERR) {
>>> +        return broker->err_no;
>>> +    }
>>> +    return 0;
>>> +}
>>> diff --git a/libqblock/libqblock-error.h b/libqblock/libqblock-error.h
>>> new file mode 100644
>>> index 0000000..0690cfb
>>> --- /dev/null
>>> +++ b/libqblock/libqblock-error.h
>>> @@ -0,0 +1,50 @@
>>> +/*
>>> + * QEMU block layer library
>>> + *
>>> + * Copyright IBM, Corp. 2012
>>> + *
>>> + * Authors:
>>> + *  Wenchao Xia   <address@hidden>
>>> + *
>>> + * This work is licensed under the terms of the GNU LGPL, version 2 or
>>> later.
>>> + * See the COPYING.LIB file in the top-level directory.
>>> + *
>>> + */
>>> +
>>> +#ifndef LIBQBLOCK_ERROR
>>> +#define LIBQBLOCK_ERROR
>>> +
>>> +#include "libqblock-types.h"
>>> +
>>> +#define QB_ERR_MEM_ERR (-1)
>>> +#define QB_ERR_INTERNAL_ERR (-2)
>>> +#define QB_ERR_INVALID_PARAM (-3)
>>> +#define QB_ERR_BLOCK_OUT_OF_RANGE (-100)
>>> +
>>> +/* error handling */
>>> +/**
>>> + * qb_error_get_human_str: get human readable error string.
>>> + *
>>> + * return a human readable string, it would be truncated if buf is not
>>> big
>>> + *  enough.
>>> + *
>>> + * @broker: operation broker, must be valid.
>>> + * @buf: buf to receive the string.
>>> + * @buf_size: the size of the string buf.
>>> + */
>>> +DLL_PUBLIC
>>> +void qb_error_get_human_str(struct QBroker *broker,
>>> +                            char *buf, int buf_size);
>>> +
>>> +/**
>>> + * qb_error_get_errno: get error number, only valid when err_ret is
>>> + *   QB_ERR_INTERNAL_ERR.
>>> + *
>>> + * return negative errno or 0 if last error is not QB_ERR_INTERNAL_ERR.
>>> + *
>>> + * @broker: operation broker.
>>> + */
>>> +DLL_PUBLIC
>>> +int qb_error_get_errno(struct QBroker *broker);
>>> +
>>> +#endif
>>> --
>>> 1.7.1
>>>
>>>
>>
>
>
> --
> Best Regards
>
> Wenchao Xia
>